ESD protection circuit cell

Abstract

A device includes a first bidirectional PNP circuit coupled to a first output of an communication circuit, and a second bidirectional PNP circuit coupling to a second output of the communication circuit. The first and second bi-direction PNP circuits have coupled outputs and a first breakdown voltage. A third bidirectional PNP circuit is coupled to ground via the coupled outputs of the first bidirectional PNP circuit and of the second bidirectional PNP circuit. The third bidirectional PNP circuit has a second breakdown voltage. In some arrangements, a sum of the first breakdown voltage and the second breakdown voltage exceeds 60 volts. The communication circuit can be an automotive application circuit for a serial automotive communication application. The first and second bidirectional transistor circuits can form a part of a cell of an integrated circuit having an isolation structure to sustain high voltage.

What is claimed is: 
     
       1. A clamp circuit, comprising:
 an electrostatic discharge (ESD) network, comprising:
 a first bidirectional circuit coupled to a first output of a communication circuit; 
 a second bidirectional circuit coupled to a second output of the communication circuit, the first and second bidirectional circuits having respective outputs that are coupled together and each having a first breakdown voltage, each of the first and second bidirectional circuits including a bidirectional PNP portion disposed laterally adjacent to an isolation portion, the isolation portion including first and second P-wells separated by a N-well, and each bidirectional PNP portion including a shallow N-well, and first and second P+ diffusion regions separated by an isolation region formed within the shallow N-well, and wherein the shallow N-well is formed within the first P-well of the isolation portion; and 
 a third bidirectional circuit coupled to ground and to outputs of the first bidirectional circuit and of the second bidirectional circuit, the third bidirectional circuit having a second breakdown voltage. 
 
 
     
     
       2. The clamp circuit of  claim 1 , wherein a sum of the first breakdown voltage and the second breakdown voltage exceeds 60 volts. 
     
     
       3. The clamp circuit of  claim 1 , wherein the communication circuit is an automotive application circuit. 
     
     
       4. The clamp circuit of  claim 1 , wherein the communication circuit is a serial automotive communication application. 
     
     
       5. The clamp circuit of  claim 1 , wherein the first and second bidirectional circuits form a part of a cell of an integrated circuit having an isolation structure to sustain high voltage. 
     
     
       6. The clamp circuit of  claim 1 , wherein the ESD network is part of a stacked cell where each respective cell has a respective isolation ring. 
     
     
       7. The clamp circuit of  claim 1 , wherein the ESD network is a stacked cell structure. 
     
     
       8. The clamp circuit of  claim 1 , wherein the third bidirectional transistor circuit includes a third bidirectional PNP circuit. 
     
     
       9. A device comprising:
 a first bidirectional PNP circuit coupled to a first output of a communication circuit; 
 a second bidirectional PNP circuit coupled to a second output of the communication circuit, the first and second bidirectional PNP circuits having respective outputs that are coupled together and each having a first breakdown voltage; and 
 a third bidirectional PNP circuit coupled to ground and to outputs of the first bidirectional PNP circuit and of the second bidirectional PNP circuit, the third bidirectional PNP circuit having a second breakdown voltage, 
 wherein the first and second bidirectional circuits each include a PNP portion disposed laterally adjacent to an isolation portion, each PNP portion including a pair of P+ regions between which a shallow trench isolation structure is disposed, the pair of P+ regions and the shallow trench isolation structure formed in an upper surface of a shallow N-well, and the isolation portion including first and second P-wells separated by a second N-well that is separated from the shallow N-well by the first P-well, and wherein the shallow N-well is formed within the first P-well of the isolation portion. 
 
     
     
       10. The device of  claim 9 , wherein a sum of the first breakdown voltage and the second breakdown voltage exceeds 60 volts. 
     
     
       11. The device of  claim 9 , wherein the communication circuit is an automotive application circuit. 
     
     
       12. The device of  claim 9 , wherein the first and second bidirectional PNP circuits form a part of a cell of an integrated circuit having an isolation structure to sustain high voltage. 
     
     
       13. The device of  claim 9 , wherein at least one of the first and second P-wells of the isolation portion comprises a high voltage P-type well (HVPW) and the second N-well of the isolation portion comprises a high voltage N-type well (HVNW) to provide a pn junction diode. 
     
     
       14. The device of  claim 9 , wherein the device is a clamp circuit having the ESD network forming a part of a stacked cell where each respective cell has a respective isolation ring. 
     
     
       15. The device of  claim 9 , wherein the ESD network is a stacked cell structure. 
     
     
       16. The device of  claim 9 , wherein the first bidirectional PNP circuit and the second PNP bidirectional circuit are formed on a first substrate, and the third bidirectional PNP circuit is formed on a second substrate. 
     
     
       17. A method of providing electrostatic discharge protection to a communication circuit, comprising:
 coupling a first bidirectional circuit to a first output of the communication circuit; 
 coupling a second bidirectional circuit to a second output of the communication circuit, the first and second bidirectional circuits having respective outputs that are coupled together and each having a first breakdown voltage, each of the first and second bidirectional circuits including a bidirectional PNP portion disposed laterally adjacent to an isolation portion, the isolation portion including-first and second P-wells separated by a N-well, and each bidirectional PNP portion including a shallow N-well, and first and second P+ diffusion regions separated by an isolation region formed within the shallow N-well, and wherein the shallow N-well is formed within the first P-well of the isolation portion; and 
 coupling a third bidirectional circuit to ground and to the outputs of the first bidirectional circuit and of the second bidirectional circuit, the third bidirectional circuit having a second breakdown voltage. 
 
     
     
       18. The method of  claim 17 , wherein the first bidirectional circuit and the second bidirectional circuit form a first cell and the third bidirectional circuit forms a second cell, and wherein each cell has its own isolation ring for preventing leakage current.